Our long term goal is to understand why some individuals are vulnerable or resilient to the potentially adverse effects of chronic stress. Chronic stress is a critical factor contributing to the development of affective and anxiety disorders and can precipitate relapse of depression and post-traumatic stress disorder. This intimate association between repeated/chronic stress and affective and anxiety disorders underscores the need to understand fully the neural circuitry that regulates the physiological and behavioral consequences of repeated stress.

We approach this need in two ways, using rat models. First, we are examining the neural circuits that are impacted by stress exposure and how these circuits, in turn, produce dysfunction in physiology and behavior. In these studies, we use state-of-the-art neuroscience techniques, including multiplex PCR and protein arrays,optogenetic stimulation of peptide release, in situ hybridization, tract tracing, immunocytochemistry and western blots, as well as behavioral and pharmacological approaches that allow us to pinpoint the brain regions of interest and to identify specific neural mechanisms. We have used these technical approaches to examine specific cortico-limbic circuits important for regulating stress reactivity. We have found that neural adaptations to chronic stress develop over time and, once developed, are stable.

Second, we examine individual differences in reactivity to stress to understand how some are vulnerable and others resistant to the effects of stress. We have observed that individual differences in how adult animals cope with defeat by a dominant animal have neural and behavioral repercussions. In addition, we have observed that prenatal and early postnatal environmental factors produce enduring effects on neural circuitry regulating stress reactivity. Recently, we have observed the stress of isolation during adolescence produces enduring effects on behavioral, neuroendocrine and neural reactivity to stress and these effects are more pronounced in females. In these developmental studies, we are collaborating to use emerging neuroimaging techniques to examine development of fiber tracts and gray matter in addition to the techniques mentioned above.

Appointments

Assistant Professor of Anesthesiology and Critical Care at University of Pennsylvania School of Medicine (2005 – 2012)

Associate Professor of Anesthesiology and Critical Care at University of Pennsylvania School of Medicine (2012– present)